Made of 2-ply rubber, the top (gray) layer is static dissipative, and the bottom (black) layer is conductive. Easy to cut into workstation mats for soldering (resists heat up to 500F), used as floor runner for assembly lines, or as a tray liner for holding electronics on racks these mats are widely used for anti static or electrostatic discharge (ESD) protection in a variety of workplaces.